A monomolecular film may be formed by a chemical adsorption process of a chlorosilane-based surface active material having a long hydrocarbon chain to a substrate surface. The substrate can be aluminum or stainless steel and can have hydroxyl groups attached.
The method of adsorbing a film to a substrate surface involves a hydrochloric acid removal reaction. This reaction takes place between hydroxyl groups on a substrate surface and chlorosilyl groups of the chlorosilane-based surface active material.
The surface of an aluminum or a stainless steel substrate is rendered an anti-contaminating, heat-resistant, weather-resistant and wear-resistant by coating the substrate surface with a fluorocarbon-based thin film.
This is usually done by rendering the surface of an aluminum substrate coarse by means of a wire brush or chemical etching, coating with a primer and then with a paint. The paint is usually prepared by suspending fluorocarbon-based fine particles of ethylene polytetrafluoride in ethanol, drying, and then baking at about 400.degree. C. for about one hour. The procedure fixes the fluorocarbon-based polymer to the substrate surface.
Known methods of adsorbing the chlorosilane-based surface active material, however, do not substantially increase the anti-contaminating property of the film.
Known methods of coating a fluorocarbon-based coating film, on the other hand, permit ready formation of the anti-contaminating film. However, there is a limit to the degree in which the polymer is anchored to the substrate. Therefore, the method is inadequate when used in manufacturing high mechanical strength apparatuses which require anti-contaminating, heat-resistant, weather-resistant and wear-resistant coatings. These apparatuses include, for example, hot plates, rice cookers and other electric products, vehicles, industrial machines, glass lenses, mirrors, etc.
Moreover, with the prior art coating method, a coating film thickness of several tens of microns is necessary at least in order to prevent pin-hole generation. Therefore prior art films lack transparency or brilliancy.